OHAA Air-Operated Double-Diaphragm (AODD) pumps are classified as reciprocating, positive-displacement-style pumps. They operate by displacing fluid from one of its two liquid chambers upon each stroke completion. To operate, the OHAA AODD pumps require a given amount of pressure and air volume to deliver the proper amount of fluid.

WORKING PRINCIPAL:-


LEFT STROKE:-


The air valve directs pressurized air to the back side of diaphragm A-Wing. The compressed air is applied directly to the liquid column separated by elastomeric diaphragms. The diaphragm acts as a separation membrane between the compressed air and liquid, balancing the load and removing mechanical stress from the diaphragm.

The compressed air moves the diaphragm away from the center block of the pump. The opposite diaphragm is pulled in by the shaft connected to the pressurized diaphragm. Diaphragm B-Wing is on its suction stroke; air behind the diaphragm has been forced out to the atmosphere through the exhaust port of the pump. The movement of diaphragm B-Wing toward the center block of the pump creates a vacuum within chamber B. Atmospheric pressure forces fluid into the inlet manifold forcing the inlet valve ball off its seat. Liquid is free to move past the inlet valve ball and fill the liquid chamber

MIDSTROKE:-

When the pressurised diaphragm, Diaphragm A-Wing, reaches the limit of its discharge stroke, the air valve redirects pressurised air to the backside of Diaphragm B-Wing. The pressurised air forces Diaphragm B-Wing away from the center while pulling Diaphragm A-Wing toward the center via the common shaft. Diaphragm B-Wing is now on its discharge stroke, which forces the inlet valve ball in Chamber B-Wing onto its seat due to the hydraulic forces developed in Chamber B-Wing and the manifold of the pump. These same hydraulic forces lift the discharge valve ball off its seat in Chamber B-Wing; while the opposite discharge valve ball in Chamber A-Wing is forced onto its seat, forcing fluid to flow through the pump discharge. The movement of Diaphragm A-Wing toward the center of the pump creates a vacuum within Chamber A-Wing and the atmospheric pressure forces fluid into the inlet manifold of the pump. The inlet valve ball in Chamber A-Wing is forced off its seat, allowing the fluid being pumped to fill Chamber A-Wing from the inlet manifold.

RIGHT STROKE:-

At the completion of the stroke, the air valve again redirects air to the back side of diaphragm A-Wing, which starts diaphragm B-Wing on its exhaust stroke. As the pump reaches its original starting point, each diaphragm has gone through one exhaust and one discharge stroke. This constitutes one complete pumping cycle. The pump may take several cycles to completely prime depending on the conditions of the application.